Musical instrument



Dec. 3, 1929.

w. BLANK 1,737,910

MUSICAL INSTRUMENT Filed Feb. 3, 1927 fig. 4 /7g 2 Patented 3, 1929 WILHELM BLANK, 9E PLAUEN,

MUSICAL INSTRUMENT Application filed February 3, 1327, Serial No.

This invention relates to musical instrumerits, particularly to electric pianos of that kind well known in art in which the sounds or tones are produced by electric currents dow in in circuits closed by keys or an automatica ly operating device. In order to produce an oscillation of the electric currents coming from any source, such as a galvanic battery or an accumulator or the like, said oscillations being shaped in a sinelike manner, I use a microphone filled with coal grit or any other microphone capable of changing mechanical oscillations of any parts in correspondin Variations of electric currents. To the mem rane of said microphones a bridge or cone or any other connecting means is attached, the free end of which touches any oscillatory part, f.'i. a string, a plate spring fastened on one end of it-or a tuning fork. The oscillations of these parts are produced by appertaining electro-magnets influenced by currents controlled by said microphones.

In order that the principle thereof may be readil understood I have disposed a single embo iment thereof by way of example in the accompanying drawing, wherein Fig. 1 shows a vertical section through a piano embodying the invention,

Fig. 2 illustrates the electrical connection of the operating parts of the piano shown in Fig. 1, and

Fig. 3 is a detail showing the position of an oscillatory string relative to its electromagnet.

A string 1 is stretched between the fastening points 2 and 3 in any manner well known in art so-that the celerity of the oscillations of the string and the height of the tone produced by it can be regulated.

The electro-magnet 4 is arranged in relation to the string 1 in such a manner, that the string can move freely between the poles 5 of the magnet 4 tapered one to the other. In this way the string is drawn by weak currents to the narrowest points between the poles.

The oscillations of the string 1 are transferred to the membrane or diaphragm 7 of the microphone by'a bridge or cone or any other connecting piece 6 weakly pressed 165,586, and in @errnany February 11, 19263.

against the string 1 by the microphone. This is removably attach d by screws 71 to a lever 72 one end of which is hinged to a road 73 supported by the casin of the piano, whilst the other end of said lever 72 is adjustably an held by a screw l arranged in a road 75 also mounted in the casing of the piano. Between the membrane Y and the counter-plate 8 of the microphone coal grit is tilled in.

In order to influence the magnet 4 in acto cordance with the oscillations of the string 1, a wire a is running from the electric source 9 to the collecting wire 6 which is one part of a contact or switch embodied by a key, or an automatically working roller, or any other es appliance well known in art and actuated in any way, for instance by depressing a key supporting the other part 10 of the contact or switch. From here a wire 0 runs to the microphone plate 8. The electric currents then pass through the coal-grit to the membrane 7 and then through the wire d, the coil 14 of the magnet at and the wire e to the collecting wire f, which is electrically con= nected with the switching arm 20 of a resistance controller. This arm 20 is moved by a pedal 21, connected with the side-arm 22 of the switching arm 20 by a rod 23, overcoming the power of the spring 24 seized on another side-arm 25 of said switching arm 20. 30 The electric currents flow through this arm 20 to a resistance coil or a row of resistances 26. One end of this coil or row is connected by means of the wire 9 to the other pole of said battery 9. The other end of the resistance 26 is connected to a telephone or loudspeaker or the like 12 by the wire it in order to make audible the electric currents, then flowing through the wires inand g also to the battery 9. The currents coming from the wire 7 are divided in accordance to the position of the switching arm 20, one part of them passing through the telephone 12 to the battery 9 and the other immediately that way. By shifting the switching arm 20 the intensity of the tones is controlled.

Between the collecting wires 1) and 7 any number of wires c'-e', 0"-e" o"'--e can be arranged, each of them hsiving a switch 10, a microphone 7, 8 and a magnet coil 14,

the microphones and enlarging the resistance of this latter, till the current is reduced so far that the magnet 4 cannot hold the oscillating part 1. hen this swings back over the original position, thus reducing the resistance of the microphone. The current then growing again influences the magnet 4 insuch a manner that it can draw again the with the help of resonators or by telephones,

altered in great varlety. Instead of a string s ring. can be used as an oscillating part.

oscillating part. This operation and'procedure is repeated in accordance with the oscillator peculiarities of the oscillating art 1. n this manner the current coming rom the electric source 9 is altered into a sinelike changin current capable of producingl a tone like t at of a violin made-audible eit er. immediately by the oscillating part loudspeakers or the like.

The arrangement above described, can be of steel-bandfastened on both ends or a plate or bar spring 1'fastened on one end of it only, or a tuning fork '1, or a membrane, or a plate attached on one edge to a iflerent kinds of such parts can be arranged in one musical instrument, for instance tuning forks for the lower tones and strings for ?the higher tones, but each of these. oscillating parts is tuned' for a determinate and appointed tone. Therefore strings are stretched in a distinct measure and platesprings are fastened on their sup ort in such a way that the lengths of their ree swinging parts can be, varied. Or in all these cases a bridge 15 can be arranged movably for influencing the oscillations of the parts. For this urpo se the microphone 7, 8 with its bridgeli (e cone "6 can be used by arranging it near the fastened end of the oscillating part indicated in the drawing by the bridge 15.

If the weak currents controlled by the microphone cannot influence the electro-magnets or a loudspeaker insufficient manner, they are to be reinforced in a well known manner.

The principle of my invention consists in using microphones capable of changing the variations of mechanical pressure produced by oscillating parts into corresponding variations of electric currents for said purpose, whereby one part of said microphones, for instance their casing, is removably supported by the casing of the'musica-l instrument. I

Having thus described one illustration and embodiment of my invention, I desire it to be be understood that although specific terms are employed, they are used in a generic and descriptive sense and not for purposes of limitation. Changes and variations may be made in the construction by which the invent1on claimed is carried into effect without departing from the spirit or scope of the invention.

Having thus described the invention, what I claim as new is parts influenced by electro-magnets and influencing mechanically microphones capable of changing the variations of mechanical pressure of said oscillating parts into corresponding variations of electric currents flowing through said microphones, said microphones removably, supported by the casing of the musical instrument. 2. A musical instrument having in combination of oscillating parts, electro-magnets influencing said oscillating parts, an electric source, wires connected to said source and forming circuits for influencing said'electromagnets and switches for closing cuits, with microphones mechanically connected to said oscillating parts and capable of changing the variations of mechanical pressure of said oscillating parts into com sponding variations of electric currents flowing in said circuits and influencing said elec-- ,tro-magnets, said microphones removably supported by the casing of the musical instrument.

3. A musical instrument having in combination of oscillating parts, electro-magnets influencing said oscillating parts, an electric source, wires connected to said source and said electro-magnet by forming circuits and switches for closing said circuits, with microphones removably connected to said oscillate. ing parts by connecting means capable of transferring the oscillations of said oscillating parts into movements of the membrane of said microphones capable of changin the variations of mechanical pressure of sai oscillating parts into corresponding variations of electric currents flowing insaid circuits and influencing said electro-magnets, said microphones removably supported by the casing of the musical instrument.

4. A musical instrument having in combination of oscillating parts, electro-magnets influencing said oscillating parts, an electric source, wires connected to said source and to the coils of said electro-magnets by forming circuits and switches for closing said circuits, with microphones removably connected to said oscillating parts by connecting means capable of transferring the oscillations of said oscillating parts into corre onding movements of the membrane of sai microphones capable of changin the variations of mechanical pressure of said oscillating parts into corresponding variations of electric currents flowing in said circuits and influencing said electro-magnets and with a removable resistance device for dividing the currents flowing through said circuits one part of said 1. A musical instrument having oscillating h said cirgilirrents going to a device for making it audie. a V 5. A musical instrument having in combination of strings, electro-magnets mfluencing said strings and embracing them by poles tapered or inclined one relative to the other, an electric source, wires connected to said source and the coils of said electro-magnets by forming circuits and switches for closing said circuits, with microphones connected to said strings'by connecting means capable oi transferring the oscillations of said strings into corresponding movements of the membrane of said microphones capable of changing the variations of mechanical pressure of said strings into corresponding variations of electric currents flowing in said circuits and influencing said electro-magnets and with a removable resistance device for dividing the currents flowing in said circuits one part of said currents going to a device for making it audible, said microphones removably supported by the casing of the musical instrument.

I In witness whereof I aflix my-si ature.

WILHELM LANK. 

